a test

.travis.yml

@@ -151,7 +151,7 @@ install:
          (cd ${LLVM_DIR}/build/projects/libcxx && make install -j2)
          (cd ${LLVM_DIR}/build/projects/libcxxabi && make install -j2)
        fi
-       export CXXFLAGS="-nostdinc++ -isystem ${LLVM_DIR}/install/include/c++/v1"
+       export CXXFLAGS="-stdlib=libc++ -nostdinc++ -isystem ${LLVM_DIR}/install/include/c++/v1"
        export LDFLAGS="-L ${LLVM_DIR}/install/lib -l c++ -l c++abi"
        export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:${LLVM_DIR}/install/lib"
        export PATH="${LLVM_DIR}/clang/bin:${PATH}"